Effect of Long-term Integrated Nutrient Supply on Soil Chemical Properties,Nutrient Uptake and Yield of Rice

摘要

An experiment on long-term integrated nutrient supply in rice-rice cropping system was conducted for 31 seasons during Kharif and Rabi from 1988 to 2003-04 under irrigated conditions.After 31 seasons of rice cropping,there was an increase in organic carbon from 0.54 to 0.63% and available P from 15 to 20 kg ha~(-1) in treatments that received organic and chemical nutrition and 18 kg ha~(-1) with continuous application of recommended dose of fertiliser over initial available P status (24.4 kg ha~(-1)).There was an increase of 25 kg ha~(-1) (RD) of K with 100% RD NPK fertiliser and 17 to 27 kg ha~(-1) of K with application of 50 to 75% of RD along with 25 to 50% of the RD N through organic source.On the other hand,there was a decrease of 55 kg ha~(-1) K without application of any nutrients and 4-14 kg of K decrease with 50 - 75% of RD NPK fertiliser over the initial value.From the beginning of experiment (1988-89),combination of NPK with organic manures recorded higher grain yield in a year (8.83 to 11.95 t ha~(-1)).Highest sustainable yield index (54.85% in Kharif and 47.38% in Rabi) was observed with 100% RD of NPK alone.The highest N,P and K uptake was recorded with application of 50% RD NPK+ 50% N through glyricidia.